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-// Copyright (c) 2011 AlphaSierraPapa for the SharpDevelop Team
-//
-// Permission is hereby granted, free of charge, to any person obtaining a copy of this
-// software and associated documentation files (the "Software"), to deal in the Software
-// without restriction, including without limitation the rights to use, copy, modify, merge,
-// publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons
-// to whom the Software is furnished to do so, subject to the following conditions:
-//
-// The above copyright notice and this permission notice shall be included in all copies or
-// substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
-// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
-// PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE
-// FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-// DEALINGS IN THE SOFTWARE.
-
-using System;
-using System.Diagnostics;
-using System.Linq;
-using ICSharpCode.NRefactory.CSharp;
-
-namespace ICSharpCode.Decompiler.Ast.Transforms
-{
- /// <summary>
- /// Decompiles query expressions.
- /// Based on C# 4.0 spec, §7.16.2 Query expression translation
- /// </summary>
- public class IntroduceQueryExpressions : IAstTransform
- {
- readonly DecompilerContext context;
-
- public IntroduceQueryExpressions(DecompilerContext context)
- {
- this.context = context;
- }
-
- public void Run(AstNode compilationUnit)
- {
- if (!context.Settings.QueryExpressions)
- return;
- DecompileQueries(compilationUnit);
- // After all queries were decompiled, detect degenerate queries (queries not property terminated with 'select' or 'group')
- // and fix them, either by adding a degenerate select, or by combining them with another query.
- foreach (QueryExpression query in compilationUnit.Descendants.OfType<QueryExpression>()) {
- QueryFromClause fromClause = (QueryFromClause)query.Clauses.First();
- if (IsDegenerateQuery(query)) {
- // introduce select for degenerate query
- query.Clauses.Add(new QuerySelectClause { Expression = new IdentifierExpression(fromClause.Identifier) });
- }
- // See if the data source of this query is a degenerate query,
- // and combine the queries if possible.
- QueryExpression innerQuery = fromClause.Expression as QueryExpression;
- while (IsDegenerateQuery(innerQuery)) {
- QueryFromClause innerFromClause = (QueryFromClause)innerQuery.Clauses.First();
- if (fromClause.Identifier != innerFromClause.Identifier)
- break;
- // Replace the fromClause with all clauses from the inner query
- fromClause.Remove();
- QueryClause insertionPos = null;
- foreach (var clause in innerQuery.Clauses) {
- query.Clauses.InsertAfter(insertionPos, insertionPos = clause.Detach());
- }
- fromClause = innerFromClause;
- innerQuery = fromClause.Expression as QueryExpression;
- }
- }
- }
-
- bool IsDegenerateQuery(QueryExpression query)
- {
- if (query == null)
- return false;
- var lastClause = query.Clauses.LastOrDefault();
- return !(lastClause is QuerySelectClause || lastClause is QueryGroupClause);
- }
-
- void DecompileQueries(AstNode node)
- {
- QueryExpression query = DecompileQuery(node as InvocationExpression);
- if (query != null)
- node.ReplaceWith(query);
- for (AstNode child = (query ?? node).FirstChild; child != null; child = child.NextSibling) {
- DecompileQueries(child);
- }
- }
-
- QueryExpression DecompileQuery(InvocationExpression invocation)
- {
- if (invocation == null)
- return null;
- MemberReferenceExpression mre = invocation.Target as MemberReferenceExpression;
- if (mre == null)
- return null;
- switch (mre.MemberName) {
- case "Select":
- {
- if (invocation.Arguments.Count != 1)
- return null;
- string parameterName;
- Expression body;
- if (MatchSimpleLambda(invocation.Arguments.Single(), out parameterName, out body)) {
- QueryExpression query = new QueryExpression();
- query.Clauses.Add(new QueryFromClause { Identifier = parameterName, Expression = mre.Target.Detach() });
- query.Clauses.Add(new QuerySelectClause { Expression = body.Detach() });
- return query;
- }
- return null;
- }
- case "GroupBy":
- {
- if (invocation.Arguments.Count == 2) {
- string parameterName1, parameterName2;
- Expression keySelector, elementSelector;
- if (MatchSimpleLambda(invocation.Arguments.ElementAt(0), out parameterName1, out keySelector)
- && MatchSimpleLambda(invocation.Arguments.ElementAt(1), out parameterName2, out elementSelector)
- && parameterName1 == parameterName2)
- {
- QueryExpression query = new QueryExpression();
- query.Clauses.Add(new QueryFromClause { Identifier = parameterName1, Expression = mre.Target.Detach() });
- query.Clauses.Add(new QueryGroupClause { Projection = elementSelector.Detach(), Key = keySelector.Detach() });
- return query;
- }
- } else if (invocation.Arguments.Count == 1) {
- string parameterName;
- Expression keySelector;
- if (MatchSimpleLambda(invocation.Arguments.Single(), out parameterName, out keySelector)) {
- QueryExpression query = new QueryExpression();
- query.Clauses.Add(new QueryFromClause { Identifier = parameterName, Expression = mre.Target.Detach() });
- query.Clauses.Add(new QueryGroupClause { Projection = new IdentifierExpression(parameterName), Key = keySelector.Detach() });
- return query;
- }
- }
- return null;
- }
- case "SelectMany":
- {
- if (invocation.Arguments.Count != 2)
- return null;
- string parameterName;
- Expression collectionSelector;
- if (!MatchSimpleLambda(invocation.Arguments.ElementAt(0), out parameterName, out collectionSelector))
- return null;
- LambdaExpression lambda = invocation.Arguments.ElementAt(1) as LambdaExpression;
- if (lambda != null && lambda.Parameters.Count == 2 && lambda.Body is Expression) {
- ParameterDeclaration p1 = lambda.Parameters.ElementAt(0);
- ParameterDeclaration p2 = lambda.Parameters.ElementAt(1);
- if (p1.Name == parameterName) {
- QueryExpression query = new QueryExpression();
- query.Clauses.Add(new QueryFromClause { Identifier = p1.Name, Expression = mre.Target.Detach() });
- query.Clauses.Add(new QueryFromClause { Identifier = p2.Name, Expression = collectionSelector.Detach() });
- query.Clauses.Add(new QuerySelectClause { Expression = ((Expression)lambda.Body).Detach() });
- return query;
- }
- }
- return null;
- }
- case "Where":
- {
- if (invocation.Arguments.Count != 1)
- return null;
- string parameterName;
- Expression body;
- if (MatchSimpleLambda(invocation.Arguments.Single(), out parameterName, out body)) {
- QueryExpression query = new QueryExpression();
- query.Clauses.Add(new QueryFromClause { Identifier = parameterName, Expression = mre.Target.Detach() });
- query.Clauses.Add(new QueryWhereClause { Condition = body.Detach() });
- return query;
- }
- return null;
- }
- case "OrderBy":
- case "OrderByDescending":
- case "ThenBy":
- case "ThenByDescending":
- {
- if (invocation.Arguments.Count != 1)
- return null;
- string parameterName;
- Expression orderExpression;
- if (MatchSimpleLambda(invocation.Arguments.Single(), out parameterName, out orderExpression)) {
- if (ValidateThenByChain(invocation, parameterName)) {
- QueryOrderClause orderClause = new QueryOrderClause();
- InvocationExpression tmp = invocation;
- while (mre.MemberName == "ThenBy" || mre.MemberName == "ThenByDescending") {
- // insert new ordering at beginning
- orderClause.Orderings.InsertAfter(
- null, new QueryOrdering {
- Expression = orderExpression.Detach(),
- Direction = (mre.MemberName == "ThenBy" ? QueryOrderingDirection.None : QueryOrderingDirection.Descending)
- });
-
- tmp = (InvocationExpression)mre.Target;
- mre = (MemberReferenceExpression)tmp.Target;
- MatchSimpleLambda(tmp.Arguments.Single(), out parameterName, out orderExpression);
- }
- // insert new ordering at beginning
- orderClause.Orderings.InsertAfter(
- null, new QueryOrdering {
- Expression = orderExpression.Detach(),
- Direction = (mre.MemberName == "OrderBy" ? QueryOrderingDirection.None : QueryOrderingDirection.Descending)
- });
-
- QueryExpression query = new QueryExpression();
- query.Clauses.Add(new QueryFromClause { Identifier = parameterName, Expression = mre.Target.Detach() });
- query.Clauses.Add(orderClause);
- return query;
- }
- }
- return null;
- }
- case "Join":
- case "GroupJoin":
- {
- if (invocation.Arguments.Count != 4)
- return null;
- Expression source1 = mre.Target;
- Expression source2 = invocation.Arguments.ElementAt(0);
- string elementName1, elementName2;
- Expression key1, key2;
- if (!MatchSimpleLambda(invocation.Arguments.ElementAt(1), out elementName1, out key1))
- return null;
- if (!MatchSimpleLambda(invocation.Arguments.ElementAt(2), out elementName2, out key2))
- return null;
- LambdaExpression lambda = invocation.Arguments.ElementAt(3) as LambdaExpression;
- if (lambda != null && lambda.Parameters.Count == 2 && lambda.Body is Expression) {
- ParameterDeclaration p1 = lambda.Parameters.ElementAt(0);
- ParameterDeclaration p2 = lambda.Parameters.ElementAt(1);
- if (p1.Name == elementName1 && (p2.Name == elementName2 || mre.MemberName == "GroupJoin")) {
- QueryExpression query = new QueryExpression();
- query.Clauses.Add(new QueryFromClause { Identifier = elementName1, Expression = source1.Detach() });
- QueryJoinClause joinClause = new QueryJoinClause();
- joinClause.JoinIdentifier = elementName2; // join elementName2
- joinClause.InExpression = source2.Detach(); // in source2
- joinClause.OnExpression = key1.Detach(); // on key1
- joinClause.EqualsExpression = key2.Detach(); // equals key2
- if (mre.MemberName == "GroupJoin") {
- joinClause.IntoIdentifier = p2.Name; // into p2.Name
- }
- query.Clauses.Add(joinClause);
- query.Clauses.Add(new QuerySelectClause { Expression = ((Expression)lambda.Body).Detach() });
- return query;
- }
- }
- return null;
- }
- default:
- return null;
- }
- }
-
- /// <summary>
- /// Ensure that all ThenBy's are correct, and that the list of ThenBy's is terminated by an 'OrderBy' invocation.
- /// </summary>
- bool ValidateThenByChain(InvocationExpression invocation, string expectedParameterName)
- {
- if (invocation == null || invocation.Arguments.Count != 1)
- return false;
- MemberReferenceExpression mre = invocation.Target as MemberReferenceExpression;
- if (mre == null)
- return false;
- string parameterName;
- Expression body;
- if (!MatchSimpleLambda(invocation.Arguments.Single(), out parameterName, out body))
- return false;
- if (parameterName != expectedParameterName)
- return false;
-
- if (mre.MemberName == "OrderBy" || mre.MemberName == "OrderByDescending")
- return true;
- else if (mre.MemberName == "ThenBy" || mre.MemberName == "ThenByDescending")
- return ValidateThenByChain(mre.Target as InvocationExpression, expectedParameterName);
- else
- return false;
- }
-
- /// <summary>Matches simple lambdas of the form "a => b"</summary>
- bool MatchSimpleLambda(Expression expr, out string parameterName, out Expression body)
- {
- LambdaExpression lambda = expr as LambdaExpression;
- if (lambda != null && lambda.Parameters.Count == 1 && lambda.Body is Expression) {
- ParameterDeclaration p = lambda.Parameters.Single();
- if (p.ParameterModifier == ParameterModifier.None) {
- parameterName = p.Name;
- body = (Expression)lambda.Body;
- return true;
- }
- }
- parameterName = null;
- body = null;
- return false;
- }
- }
-}